The invention relates generally to a function selector, especially a function selector for an electronic musical instrument.
More particularly, the invention relates to a circuit for indicating the operational states of the switches in a function selector which control the performance of the various functions.
In a conventional function selector, the switches which control the performance of the various functions may be activated individually. Each of the switches is associated with a light source which indicates the operational state of the respective switch, that is, which indicates whether or not the function control by the respective switch is being performed. An electronic control unit is provided to check the operational states of the switches and serves to illuminate the light source associated with a switch when the switch is in the "on" position so that the function controlled by the switch is being performed.
A known circuit of the type described above is employed in an electronic organ. Each switch is directly connected with a function generating element and with a light source. When a switch is closed, the corresponding function generating element causes the respective function to be performed and, at the same time, the light source connected with the switch is illuminated. The switch is arrested in its closed position. The performance of the respective function is terminated and the light source is switched off by returning the switch to its initial or "off" position.
In the preceding circuit, the conductors between the switches and the function generating elements are a source of considerable expense. This is particularly true when there is a large number of functions which can be performed as is the case in an electronic musical instrument. The expense for the conductors is further increased when the switches and the function generating elements are located at a relatively great distance from one another. This is likewise frequently the case in an electronic musical instrument. Thus, it is often desired for the switches to be located in the area of the keys while the electronics for the function generating elements are situated inside the case of the instrument.